I'm having concerns with rebooting my laptop. It's a Toshiba Satellite C875-S7344 with Windows 8. I purchased a CD to help reboot but it mentioned to disable the Secure Boot. Not sure if I am using the wrong sequence but, it doesn't seem to be working. At start-up I keep getting a "Checking Media - Fail" message. Then it says "Checking Media" again, then goes to "No Bootable device - Restart System". Not sure if I have a software or hardware problem. Any help/direction would be appreciated.